This disclosure relates to a cutting insert for a tool for machining a workpiece. The cutting insert according to this disclosure is preferably an indexable cutting insert, which may be employed in a turning tool, which is preferably used in a turning tool for recess turning. This disclosure further relates to a tool comprising a cutting insert of this kind, a holder and a fastening element for fastening the cutting insert to the holder.
An exemplary cutting insert for a turning tool, which may be used for recess turning, is known from U.S. Pat. No. 6,942,434 B2.
Indexable cutting inserts of this type mostly possess three or more cutting heads, which are arranged distributed on the periphery of the cutting insert. As soon as a cutting head, or the cutting edge arranged thereon, is worn, the cutting insert can be detached from the tool holder and fixed in a new position on the tool holder, so that one of the other, hitherto unworn cutting heads is then employed. The indexable cutting inserts can therefore be used several times over in accordance with the number of their cutting heads.
In particular in recess turning, tools having a relatively large plunge depth are particularly desired. The more cutting heads are arranged distributed on the periphery of the cutting insert, the more difficult it proves, however, from a design viewpoint, to be able to ensure sufficiently large plunge depths with tools of this type. A further important factor which matters in tools for recess turning, as well as in tools for other types of turning, is the design of an as stable as possible insert seat in the tool holder.
In the tool known from U.S. Pat. No. 6,942,434 B2, the last-named factor is relatively well achieved from a technical viewpoint, since the cutting insert is in this tool fixed very stably in the tool holder and the forces acting on the cutting insert can be effectively diverted into the tool holder. In this tool, the plunge depth to be realized is, however, comparatively small.
U.S. Pat. No. 9,174,279 B2 discloses a further tool, which is advantageous as regards plunge depth compared to the tool known from U.S. Pat. No. 6,942,434 B2. For the clamping of the cutting insert is here used, however, in addition to the customarily used clamping screw, a further component, which as a type of halfmoon-shaped clamping element engages in the bore provided in the cutting insert. Such additional clamping elements are not only difficult to produce, but also increase the production costs overall.